I do not know about a GM "klaxon" horn.
A "trumpet" style horn ws standard equipment on the intake manifold from 47-52.
In 1953, a single "seashell" style horn was standard equipment, mounted on the intake manifold.
Dual seashell style horns were optional/accessory equipment 47-55st
They were mounted in various locations 47-53, including on the intake manifold or on the firewall on the heater side.
In 1954, the standard (and optional dual) "seashell" horns we mounted on the from of the radiator housing.
